Positive stop for lifting jacks



.h me 23, 1925 7 1,543,486

c. w. RIPSCH ET AL POSITIVE STOP FOR LIFTING JACKS Filed June 5, 1921 2Sheets-Sheet l INVENTORS CMwaLtxw/F/Psnaf. Jvntsc rnwzcyg ATTORNEY June23', 1925. 1,543,486

c. w. RIPSCH ET AL POSITIVE STOP FOR LIFTING JACKS Filed June 25, 1921 2Sheets-Sheet 2 INVENTORS cur/met: w 19/1,!- .Jint; 61

ATTORNEY Patented June 23, 1925.

UNITED STATES PATENT OFFICE.

CHARLES WILLIAM RIPSOI-I AND JAMES C. DAVVLEY, OF DAYTON, OHIO,ASSIGNORS TO JOYCE-CRIDLAND COMPANY, OF DAYTON, OHIO, A CORPORATION OFOHIO.

POSITIVE STOP FOR LIFTING JACKS.

Applicatien filed June 25, 1921. Serial No. 480,302.

To, all whom it may concern..-

Be it known that we, CHAnLEs W. Rirsorr and Jaime C. DAWLEY, citizens ofthe United States, residin at Dayton, in the county of Montgomery andState of Ohio, have invented certain new and useful 1m: proveinents inPositive Stops for Lifting Jacks, of which the following isaspecification, reference being had therein to the accompanying drawing.

This invention relates to lifting jacks and the like, and moreparticularly to means for positively limiting the upward, movement ofthe lifting element of a lifting jack or the like. i

One object of the invention is to provide a simple, effective means forpreventing an excessive upward movement from being imparted to thelifting element, thereby preventing accidents and the breakage of themechanism. 1 V v A further object of the invention is to provide meansfor causing the lifting element to be automatically lowered when it hasbeen elevated to a, predetermined height and for checking this downwardmovement when the lifting element has reached a posi tion below saidpredetermined height.

Other objects of the invention will appear as the mechanism is describedin detail.

In the accompanying drawings Fig. 1 1s a vertical sectional view of ajack embodying our invention, taken on the line ll of Fig. 2; Fig. 2 isa transverse sectional view taken on the line 22 of. Fig. 1; Fig. 3 is adetail View of the controlling device; and Fig. at is a detail view ofthe actuating member forthe controlling device.

In these drawings we have illustrated one embodiment of our inventionand have shown the same as applied to a self l0wer ing jack of the typeshown and. described in Patent No. 1,3 9,101, granted to us August 10,1920, but it will be'understood that the invention is not limited tojacks of this type but may be employed in jacks or lifting devices ofvarious kinds.

I -The jack here illustrated is a high pow.- ered jack having a capacityof seventy-five tons and it comprises a base 1 hi-iving an upwardlyextending hollow standard 2. ixed in the upper end of the hollowstandard is a nut 3 in which is journaled a screw threaded shank 4 of a.lifting el ment The lifting element isprovided at its upper end with aload engaging member, or cap, 6, which is rotatable relativelythereto'and, in the present instance, is provided with a ball bearing 7interposed between the lower surface of the cap andv the flat uppersurface of the beveled gear 8 carried by the lifting element. Secured tothecap Grand extending about the standard 2 of the base is a housing 9,the lower portion of which engages the outer surface 'of the standardand serves to guide the lifting element in its vertical movement. Thelifting element is actuated by means of the beveled gear 8 which isrigidly secured thereto and which meshes with a beveledgear 10 mountedon a shaft 11 journaled in the housing 9. As here shown, the housing 9has secured to one side thereof a gear case comprising an inner wall 12,which closes an opening in the side of the housing 9 and thus forms apart of said housing, and an outer wallor casing 13. The shaft 11 of thegear 10 is journaled at. its inner end in a bracket let carried by thehousing 9 and has its outer portion journaled in bearings formed in thewalls 12 and 13.0f the gear casing. Rigidly secured to the shaft 11within the gear casing is a gear 15 which meshes with a gear 16 securedto a shaft 19 also journaled in the walls 12 and 13 and projectingbeyond the wall 13 to receive an actuating device.

This actuating device is here shown as a ratchet 20 with whichcooperates a lever 21 carrying the pawl (not shown). The pitch of thethread on the shank 4- 0f the lifting element is such that under anormal load the lifting element will move downwardly by gravity andmeans are provided for controlling this downward movement. In-theparticular ack here shown a worm wheel 22 is loosely mounted on theshaft 19.,and is adapted to be connected therewith, when theliftingelement moves downwardly, by a clutch 23, so that the worm gear willrotate only when the lifting .element is moved downwardly. Theworm.wheel-22 meshes with a worm 24 mounted on a shaft 25 and the Wormand worm gear have their spirals arranged ,at such a pitch that thewormwill be driven by the worm wheel. Rigidly secured to the shaft 25 is asecond worm wheel 26 which meshes with a worm 27, the spirals of thisworm and Worm wheel also being such that the worm wheel will drivelifting element.

the worm. A controlling device is applied to the worm 27 to control thedownward movement of the load and in the present instance thiscontrolling device comprises a brake consisting of a drum 28 rigidlysecured to the reduced portion of the worm 27. Cooperating with thisbrake drum is a friction device, such as a pair of friction shoes 30which are pivotally mounted at one side of the drum and provided on theother side of the drum with arms 31 which are acted upon by a spring 32to move the shoes into frictional contact with the drum and thus holdthe latter against rotation. To permit the load to move downwardly thearms 31 are separated against the tension ofthe spring and, as hereshown, a stud 33 is mounted in the wall of the gear casing and has itsinner portion extending between the two arms and flattened so that whenthe stud is rotated the flattened portion thereof will engage the armswith a cam action and separate the same. The outer end of the stud 33extends beyond the wall of the housing and has secured thereto anactuating lever 34 by means of which the stud may be actuated and themovement of the load controlled.

It will be apparent from the foregoing description that the brake isnormally set and will prevent the downward movement of the load in theintervals between the operation of the lever which actuates the Topreventthe lifting element from being elevated above a pre determinedheight we have provided means for automatically actuating thecontrolling device to release the lifting element and permit the latterto move downwardly. Consequently, when the lifting element reaches thispredetermined height it will be released and will move downwardly assoon as the pressure on the operating lever for the lifting element isrelieved, and any further operation of the lever would merely result inthe load being moved up and'down without the possibility of any unduepressure being applied to any part of the mechanism which might resultin breakage or of other accidents due to the excessive movement of thelifting element. To so actuate the controlling device, the standard andthe con trolling device are provided with cooperating parts which arebrought into operative relation just before the lifting element reachesthe prescribed limit of its movement, so that the further movement ofthe lifting element will cause the controlling device to be actuated.

In the particular embodiment of the in vention here illustrated we havesecured to the actuating lever 34 for the controlling device, aprojection, or finger, 35 which extends through a slot 36 in the wall ofthe housing andlias connected therewith a part,

adapted to engage a fixed stop carried by the standard. In the presentinstance, we have connected with the projection, or finger, 35 a rod 37which is mounted in a channel v38 formed in the wall of the housing 9,and has secured thereto a stop 39 which, when the lifting element andhousing have been moved upwardly a predetermined distance, will engage afixed stop on the standard. The fixed step may be of any suitablecharacter but inasmuch as the housing which carries the operatingmechanism for the jack is ro-tatably mounted on the standard it will beapparent that the jack may be operated with the movable stop 39 adjacentto any part of the standard. It is, therefore, desirable that the fixedstop be of such a character that it will cooperate with the movable stopin any position occupied by the latter. We have, therefore, shown thefixed stop as annular in form, and, in the present construction itcomprises a flange 40 carried by the nut 3 and overlapping the edge ofthe standard and the channel 38 in the housing. Consequently, anymovement of the lifting element beyond the prescribed limit will bringthe stops into engagement thus checking the movement of the rod 37 andpermitting the housing, and the controlling device, which is carriedthereby, to move relatively to the rod, thereby causing the actuatinglever 34 to be operated to release the brake. As soon as the liftingelement has moved downwardly far enough to relieve the pressure on therod 37 the brake will again be set, by the action of the spring 32, andthe further downwardmovement of the lifting element prevented. V

The stop 39 is preferably adjustable on the rod 37 so that the height atwhich the movement of the lifting element will be interrupted may beregulated. As here shown, the stop 39 is in the form of a. nut screwthreaded onto the lower end of the rod 37 and held in adjusted positionsby means of a am nut 41. A spring 42 acts on the stop 39 to counterbalance the weight of the stop and the rod so that normally these willnot interfere with, or have a tendency to cause the operation of, theactuating lever 34 for the controlling device. Consequently, at alltimes except when the stop 39 is in engagement with the fixed stop onthe standard the controlling device may be manipulated in the usualmanner. The wall of the housing 9 is provided with an opening, normallyclosed by a screw threaded cap 43, to permit access to the channel 38and the rod and stop.

The lifting element of the jack will move downward by gravity only whenunder asubstantial load and, consequently, if the jack is run up withoutload the release of the brake will not operate to check the movement ofthe lifting element. We have, there fore, provided other means forpositively limiting themovement of the lifting element when the jack isoperated without load and, as here shown, a flange 40 is secured to thenut 3, or if desired to the standard 2, and extends beyond the edge ofthe standard and into the path of ashoulder 45 formed near the lower endof the housing 9 so that when the lifting element reaches the upperlimit of its movement the shoulder 45 will engage the flange 44 andprevent the further movement of the lifting element. hen the jack isoperated under a heavy load the power required to elevate the load is sogreat that if a rigid stop,'such as the parts 45 and 40, is employed itfrequently happens that the operator will not know when the stops havecome into engagement and will continue to apply power to the jack, whichmay result in breakage or damage of some kind, but when the jack isoperated without load only a small amount of power is required toelevate the lifting element and the operator will know instantly whenthe rigid stops contact one with the other and will discontinue theapplication of power thereto. It will be noted that the stops 39 and 40are so arranged that they will cause the operation of the controllingdevice before the stops 40 and 45 come into engagement. Consequently, ifthe jack is operated under load the stops 40 and 45 need not come incontact. It will also be noted that the stops 40and 45 are of such acharacter that they will not only limit the upward movement of thelifting element relatively to the standard but will prevent the standardfrom running out of the housing and becoming separated from the liftingelement in the event of the jack being lifted above the ground.

The operation of the device will be readily understoodfrom the foregoingdescription and it will be apparent that we have provided a very simpleand highly efiicient means for positively preventing the movement of thelifting element above a predetermined height and while we have shown anddescribed one embodiment of our invention we wish it to be understoodthat we do not desire to be limited to the details thereof as variousmodifications may occur to a person skilled in the art.

Having now fully described our invention what we claim as new and desireto secure by Letters Patent, is: v

1. In a lifting jack, a lifting element, actuating means for saidlifting element, means to control the downward movement of said liftingelement, and means to automatically operate said controlling means whensaid lifting element has been elevated to a predetermined height andthus permit said lifting element to move downwardly.

2. In a lifting jack, a lifting element, actuating means for elevatingsaid lifting element, a controlling device operating normally to preventthe downward movement of said lifting element, and means toautomatically render said cont-rolling device inoperative when saidlifting element has been elevated to a predetermined height.

3. In a lifting jack, a lifting element, actuating means for elevatingsaid lifting element, a brake operating normally to prevent the downwardmovement of said lifting element, and means to automatically actuatesaid brake to release said lifting element when the latter has beenelevated to a pre-' determined height. 4. In a lifting jack, a liftingelement, actuating means for said lifting element, a friction drum soconnected with said lifting element that it will be rotated by thedownward movement thereof, a friction element cooperating with saiddrum, a spring to hold said friction element in operative engagementwith said drum, and means to automatically release said drum when saidlifting element has been'moved to a predetermined height.

, 5. In a lifting jack, a lifting element,

actuating means for said lifting element, a controlling device operatingnormally to prevent the downward movement of said lifting element, meanscontrolled by the movement of said lifting element for actuating saidcontrolling device to release said lifting element for downward movementwhen said lifting element has been elevated 4 to a. predeterminedheight, and to interrupt said downward movementwhen'the lifting elementhas moved toa position below said predetermined height. v

6. In alifting jack, 'a standard, a lifting element movably mounted onsaid standard, means for imparting lifting movement to said liftingelement, a device to control the downward movement of said liftingelement. and means controlled by the movement of said liftingelement'relatively to said standard to actuate said controlling device.

7. Ina lifting jack, a standard, a lifting element movably mounted onsaid standard, means for imparting movement to said lifting element. adevice to control the downward movement of said lifting element, andcooperating parts carried by said standard and said lifting element toactuate said controlling device.

8. In a lifting jack, a standard, a lifting element movably mounted onsaid standard, a device carried by one of said parts to control thedownward movement of said lifting element, means carried by the other ofsaid parts to cause said device to be actuated, and means to impartlifting movement to said lifting element.

9. In a lifting jack, a standard, a lifting element movably mounted onsaid standard, means for imparting lifting movement to said liftingelement, a device carried by and. movable with said lifting element tocontrol the downward movement thereof, and means carried by saidstandard to cause the operation of saidcontrolling device.

10. In a lifting jack, a standard, a lifting element movably mounted onsaid standard, means for imparting lifting movement to said liftingelement, a device carried by and movable with said lifting element tocontrol the downward movement thereof, and means mounted on a relativelyXed part to cause the operation of said. controlling device.

11. In a lifting ack, a standard, a lifting element movably mounted onsaid standard, means for imparting lifting movement to said liftingelement. a device carried by and movable with said lifting element tocontrol the downward movement thereof, and comprising an actuatingmember, and a part carried by said standard and arranged to impartmovement to said actuating member.

12. In a lifting 'ack, a standard, a lifting element movably mounted onsaid standard, means for imparting lifting movement to said liftingelement. a device carried by and movable with said lifting element tocontrol the downward movement thereof, and comprising an actuatingmember, a stop carried by said actuating member, and a second stopcarried by said standard and arranged in the path of the stop carried bysaid actuating member.

13. In a lifting jack, astandard, a liftin element movably mounted onsaid standard. means for imparting lifting movement to said liftingelement, a device carried by and movable with said lifting element tocontrol the downward movement thereof, and comprising an actuatingmember, a stop adjustably connected with said actuating member and apart carried by said standard and arranged to be engaged by said stop toimpart movement to said actuating member.

1 1-. In a lifting jack, a standard, a lifting element movably mountedon said standard, means for imparting lifting movement to said liftingelement, a device carried by and movable with said lifting element tocontrol the downward movement thereof, and comprising an actuatingmember. a rod connected with said actuating member and extendinglengthwise of said standard, a stop carried by said rod, and a stopcarried by said standard and arranged in the path of the first mentionedstop.

15. In a lifting jack, a standard, a lifting element movably mounted onsaid standard, means for imparting lifting movement to said liftingelement, a device carried by and movable with said lifting element tocontrol the downward movement thereof, and comprising an actuatingmember, a rod connected with said actuating member and extend inglengthwise of said standard, a stop adjustably mounted on said rod, anda part carried by said standard and arranged in the path of said stop.

16. In a lifting jack, a standard, a lifting element movably mounted onsaid standard,

means for imparting lifting movement to said lifting element, a devicecarried by and movable with said lifting element to control the downwardmovement. thereof, andcomprising an actuating device, a part operatively connected with said actuating device, a part carried by saidstandard and arranged to cause the operation of the first mentionedpart, and means to counter balance said first mentioned part and toretain said actuating device in its normal position.

17. In a lifting jack, a standard, a lifting element movably mounted onsaid standard, means for imparting lifting movement to said liftingelement, a device carried by and movable with said lifting element tocontrol the downward movement thereof, and comprising an actuatingmember, a rod connected with said actuating member, a stop mounted onsaid rod, a second stop carried by said standardand arranged in the pathof the first mentioned stop, and a spring acting on said first mentionedstop to cause said actuating member to be supported in its normalposition. I

, 18. In a lifting jack, a standard, a lifting element mounted in said.standard, means for imparting lifting movement to said lifting element,a housing carried by said lifting element and embracing said standard, adevice carried by said housing to control the downward movement of saidlifting element, said device having an actuating lever, said housinghaving a channel arranged alongside of and extending lengthwise of saidstandard, a rod connected with said actuating lever and arranged insaidchannel, a stop mounted on said rod, and a part carried by saidstandard and arranged in the path of saidstop.

19. In a lifting jack, a standard, a lifting element movably mounted onsaid standard, means for imparting lifting movementto said liftingelement, a device for controlling the downward movement of said liftingelement, said device being movable about said standard and comprising anactuating member, and a part extending about said standard and arrangedto impart movement to said actuating member when said lifting elementhas been moved to a predetermined position.

20. In a lifting jack, a standard, a lifting element movably mounted onsaid standard, means for imparting lifting movement to said liftingelement, a device carried by and movable with said lifting element tocontrol the downward movement thereof, said device being rotatableaboutsaid standard and comprising an actuating member, a stop carried bysaid actuating member, and a second stop carried by and extendingcircumferentially of said standard and so arranged that it will beengaged by the first mentioned stop when said lifting element has beenelevated to a predetermined height.

21. In a lifting jack, a standard, a lifting element movably mounted onsaid standard, means for imparting lifting movement to said liftingelement, a device carried by and movable with said lifting element tocontrol the downward movement thereof, said device being rotatable aboutsaid standard and comprising an actuating member, a stop carried by saidactuating member, and an annular flange mounted at the upper end of saidstandard and extending laterally beyond the same into the path of thefirst mentioned stop.

22. In a lifting ack, a standard, a lifting element movably mounted onsaid standard and arranged to move downwardly by gravity whenunder'load, means for imparting lifting movement to said liftingelement, a device carried by and movable with said lifting element tocontrol the downward movement thereof, means to automatically actuatesaid controlling device to release said lifting element for downwardmovement when it has been elevated to a predetermined height, and othermeans for interrupting the upward movement of said lifting element at apredetermined height when said jack is operated without load.

23. In a lifting jack, a standard, a lifting element movably mounted onsaid standard and arranged to move downwardly by gravity when underload, means for imparting lifting movement to said lifting element, adevice carried by and movable with said lifting element to control thedownward movement thereof, means to automatically actuate saidcontrolling device to release said lifting element for downward movementwhen it has been elevated to a predetermined height, a stop carried bysaid standard, and a second stop connected with said lifting element andarranged to engage the first mentioned stop when said lifting elementhas been elevated to a predetermined height.

24. In a lifting jack, a standard, a lifting element movably mounted onsaid standard and arranged to move downwardly by gravity when underload, a housing carried by said lifting element and embracing saidstandard, means carried by said housing for imparting movement to saidlifting element, a device carried by said housing to control thedownward movement of said lifting element, means to automaticallyoperate said controlling device to release said lifting element fordownward movement when it has been elevatedto a predetermined height, aflange secured to said standard at the upper end thereof and extendinglaterally beyond said standard, and a stop carried by said housing andarranged to engage said flange when said lifting element has been movedto a predetermined height.

25. In a lifting jack, a lifting element, means to actuate said liftingelement, an, operable device carried by said lifting element to controlthe movement thereof, and actuatingmeans for said device controlled bythe movement of said lifting element.

In a lifting jack, a non-rotatable nut, a lifting screw mounted in saidnut, means to actuate said lifting screw, a controlling device whichwill normally permit the upward movement of said lifting screw, andmeans controlled bv the movement of said lifting screw and acting onsaid controlling device to cause it to prevent further upward movementof said lifting screw.

In testimony whereof we aflix our signatures hereto.

CHARLES WILLIAM RIPSCH. JAMES C. DAVVLEY.

